This invention relates to apparatus for generating light effects.
It has been known to utilize a wide variety of light effects for aesthetic presentations or for influencing human well-being. For example, certain colors and abstract light patterns have a relaxing effect and are used accordingly in support of psychotherapeutic treatments or relaxation techniques. The action light effect of this kind exert on the human mood may be enhanced markedly by combining it with the playing back of acoustic signals, and especially music. For these reasons, these elements are used regularly in discotheques, concerts or other public performances as incidental to the music being performed; they are projected on available projection screens or surfaces or are scattered from reflectors composed of a multiplicity of individual facettes.
In systems of this kind, the light images obtainable are limited in variety as existing structures and the type of drive permit only a limited number of states to be obtained.
Document WO 88/05685 teaches a device for generating light effects which may be affected in dependence on a speaker signal. In this solution, the device has two apertured disks located along the beam path of a light source. One of the disks is driven in rotation and is coupled through suitable actuating means with a speaker cone so that vibrations thereof may be transmitted to the rotating disk. The actuating means comprises an entrainment member frictionally engaging the rotating apertured disk to impart movements thereto in accordance with the vibrations the speaker performs in operation. Drawbacks of this solution are its limited variability regarding the light patterns it can generate and the transmission mechanism, which is complex and thus susceptible to malfunction.
Document DE 39 22 661 A1 discloses an optokinetic device intended to generate abstract colored images. To this end, a housing having transparent side walls has therein a light source the light of which is bundled at least partly for impingement on the transparent side walls after at least one reflexion within the housing. The bottom wall of the housing is covered with a fluid maintained in a state of commotion by means of a wave generator. Also, plural optical elements having dispersing and/or collecting properties are movably mounted above the fluid. In its entirety, this assembly is supposed to reflect, disperse and bundle the light several times to as to generate playful light patterns for projection on a ground-glass screen. Despite its complex construction, the assembly generates little more than blurred light patterns of restricted variety.
It is the object of the invention to provide apparatus of the aforesaid kind which enables abstract light effects of great variety to be generated on a projection surface in a simple and inexpensive way.
This object is attained by apparatus as defined in claim 1 and specifically by apparatus comprising a liquid container having transparent top and bottom walls, which container is filled partly with a transparent liquid, and further comprising at least one light source disposed so that a light beam emitted thereby emerges from the liquid container through the top and bottom walls and is imaged on a desired projection surface, as well as an actuator having a control unit, said actuator effectively coupled to the liquid container directly or through transmitting media to perform movements generated in accordance with a prescribable pattern which imparts vibration to the fluid in the liquid container.
These measures enable pleasing and highly variable light effects to be generated with little design complexity and expense. The top surface of the fluid causes the light passing therethrouugh to be refracted in accordance with an existing wave pattern, angle of incidence and refractive indexxe2x80x94all of them reflected in the appearance of the resultant light effect.
In alternative embodiments, it is contemplated to use instead of an actuator imparting vibrations to the liquid container an actuator directly acting upon such liquidxe2x80x94e.g. by being immersed in it. Further, the bottom wall of the liquid container may have a reflective metal coating thereon. In that case, the light source is disposed so as to illuminate the liquid container at an angle from the top, for example, causing the light to be transmitted through the moving liquid surface and to impinge on the container bottom to be reflected thereby.
In another preferred embodiment of the invention, the aesthetic presentation of the light effects, which basically is independent, is coupled to the reproduction of acoustic signals. To this end, the control unit includes means for converting acoustic or electroacoustic signals to patterns of movement the-actuator is intended to perform. Actuator movements affect the formation of the wave pattern of the fluid surface and thus, ultimately, the appearance of the light effects.
The control unit is coupled preferably with acoustic playback equipment of which the playback performance determines the actuator""s pattern of movement. Accordingly, the assemblyxe2x80x94if connected to a hi-fi stereoxe2x80x94may be used readily in discotheques or in a user""s home.
In this connection, the control unit is designed preferably to have an input impedance compatible with conventional music playback equipment, such as preamplifiers or power amplifiers. Preferably the control unit includes means for matching its input impedance to the output impedance of the signal source.
Preferably the actuator comprises an electromagnetic transducer similar in structure to a loudspeaker with an electric vibrating coil. A speaker cone is not required if the coil or an armature driven by a stationary coil is connected directly with a drive for the liquid container or with an oscillating member immersed in the liquid.
The actuator control unit preferably includes a bandpass or lowpass filter dimensioned to excite the fluid in the container to perform oscillations in a desired and effective frequency band. Alternatively, the actuator itself may be designed and constructed to have bandpass or lowpass properties.
Conversion of the acoustic or electroacoustic signals input to the control unit to obtain actuator control signals is performed preferably in a manner such as to generate standing waves in the fluid. The resultant light effects are characterized by a pregnant and high-contrast appearance. Additional aesthetic effects can be obtained by optical auxiliary elements for deflecting, focussing or prismatically splitting the light beam.
The actuator may also comprise a speaker set up so that the movements of its cone are transmitted to the liquid container using the ambient air as a transmission medium. As a result, the system may be integrated in available speaker enclosures to at least partly replace one of the walls thereof.
In an alternative variant, the actuator comprises the speaker enclosure itself. In this case, at least the liquid container is attached to the speaker enclosure by suitable means such that its operating vibrations are transmitted to the fluid. In the aforesaid preferred embodiments, no complex electronic control of the light effects is necessaryxe2x80x94simple acoustic or mechanic coupling will be sufficient.
In another preferred embodiment of the invention, the actuator is effectively coupled with the side walls and/or the bottom wall of the liquid container. In that case, the actuator may specifically comprise an electric drive the movements of which may be transmitted directly to the liquid container. In an alternative variant of the invention, the actuator movements are passed on by means of pull wires attached to the bottom wall of the liquid container and to the actuator. This allows the actuator to be adapted to the requirements of each individual application with a high degree of variability.